Drugs useful in the treatment of mental depression have generally fallen within one of three categories: (1) blockers of synaptosomal uptake of norepinephrine and serotonin, (2) monoamine oxidase inhibitors and (3) psychomotor stimulants. Antidepressant drugs such as zimelidine, fluoxetine and sertraline appear to act by their ability to selectively block the pre-synaptosomal uptake of serotonin (5-hydroxytryptamine) in the brain. More recently, a group of piperazine structured compounds, including gepirone (U.S. Pat. No. 4,771,053) and buspirone (Psychopharmacology Bulletin, 22, 183 (1986), which are clinically effective anxiolytic agents, are also useful in the treatment of depressive disorders.